Re: How to super sprint?
That is a bayonet charge. To perform it, you need:
1) Weapon with a bayonet (Medic's self-loading rifle, Assault's MP18, Automatico, M97 or Model 10-A, Scout's sniper rifle except M1903 Experimental). You can equip bayonet by cllicking Customization in deployment screen and selecting it for the weapon.
2) When sprinting with weapon with bayonet, press the melee key/button. Sometimes you might have to do it twice, as for some reason game doesn't always register the first press as bayonet charge starter.
3) Your character will perform the charge. Keep in mind that during the charge you can't turn as well, and if you don't kill anyone, you won't be able to sprint and you will get penalty to running speed for few seconds. On the plus side, you will move faster during the charge and you'll be able to take a bit more damage.